Thursday, December 30, 2010

It's just a few more days until the start of the new year. To celebrate, here's a look back at some of the best of NASA's image of the day gallery from 2010. Clicking on each picture will take you back to the original image where you can learn more about the subject and download a higher resolution photo. Happy New Year!

[Space shuttle Endeavor is silhouetted against the Earth's atmosphere as it prepares to dock with the International Space Station on Feb. 9. Photo credit: NASA.]

[This Hubble photo of the Carina Nebula taken in April shows a dense area of newborn stars. Photo credit: NASA/ESA/M. Livio/Hubble 20th Anniversary Team.]

[NASA astronaut Garrett Reisman takes a self portrait during a spacewalk in May as part of the STS-132 mission. The International Space Station and Earth can be seen in the reflection of his visor. Photo credit: NASA.]

[This photo of Saturn's silhouette was taken by the Cassini probe on Feb. 13. In this image, the Sun is behind Saturn, illuminating the planet's uppermost atmosphere and the Sun-facing side of its rings. Photo credit: NASA/JPL/Space Science Institute.]

[A Hungarian stream turned red with toxic sludge is seen by a NASA satellite. On Oct. 4, an accident occurred at an aluminum oxide plant in western Hungary, spilling toxic red sludge that pooled over 6 feet deep in places, killing at least four people instantly. Photo credit: NASA.]

[A total lunar eclipse is seen on the morning of the winter solstice, Dec. 21, the first time the two events have happened on the same day in over 300 years. A lunar eclipse happens when the Earth passes between the Sun and the Moon, blocking sunlight from illuminating the Moon's surface. Photo credit: NASA.]

[Hurricane Celia was captured over the Pacific Ocean by NASA's Aqua satellite on June 24. Just five minutes after this photo was taken, the storm was upgraded to a Category 4 hurricane thanks to its sustained winds of 135 mph. The storm's well-defined eye is an indicator of its strength. Photo credit: NASA.]

[This Common Extensible Cryogenic Engine (CECE) is seen completing its final hot-fire test this summer. The engine is capable of deep throttling, or precise throttling down to allow a smooth and controlled landing. Deep throttling engines could allow spacecraft to land on unfamiliar surfaces like those on asteroids or other planets. Photo credit: NASA]

[This false-color image of the Islands of the Four Mountains, snow-capped volcanoes in Alaska's Aleutian Island chain, was taken by NASA's Terra satellite in August. Mt. Cleveland, the active volcano in the center of the image, can be seen spewing a light plume of ash and gas. Photo credit: NASA.]

[This infrared photo from the European Space Agency's Herschel Space Observatory shows the dust cloud next to the Rosette Nebula, a "stellar nursery," located about 5,000 light-years from earth in the constellation Monoceros. Photo credit: ESA/PACS & SPIRE Consortium/HOBYS Key Programme Consortia.]

[The Florida peninsula at night as seen by the crew of the International Space Station on Dec. 28, 2010. Photo credit: NASA.]

[Space Shuttle Endeavour is seen on launchpad 39-A two days before its Feb. 8 launch. Endeavour is currently scheduled to be the orbiter to make the final shuttle launch on April 1 before NASA's shuttle fleet is retired. One more flight, however, may be added after Endeavour's April launch, which would make Atlantis the last orbiter to fly. Photo credit: NASA/Bill Ingalls.]

[These two lasers originating from facilities at the Geophysical and Astronomical Observatory at the Goddard Space Flight Center keep track of orbiting satellites. These two lasers are tracking a satellite orbiting the Moon. Photo credit: NASA.]

[The space shuttle crew of STS-133 hams it up during a break in launch countdown training. Space Shuttle Discovery was first scheduled to launch on Nov. 1 but has been delayed several times due to technical problems and once for weather. The current launch date for the second-to-last space shuttle mission is scheduled for Feb. 3. Photo credit: NASA/Kim Shiflett.]

Wednesday, December 29, 2010

Researchers at the University of British Columbia are channeling brightly-colored Jewel Beetles in their development of iridescent glass that could help with energy conservation in buildings.

Iridescent objects have surfaces that appear to change color depending on the angle at which they are viewed. Common examples of iridescent objects are soap bubbles, sea shells and butterflies' wings.

The glass developed by the Canadian researchers takes advantage of the properties of iridescent materials to reflect specific wavelengths of ultra violet, visible or infrared light. The reflective properties of the glass allows it to keep warm radiation inside on cold days and outside on hot days.

To learn more about this new research that appeared recently in the journal Nature, listen to this Physics Buzz podcast below:

Tuesday, December 28, 2010

They come from the Sun. They come from interactions between cosmic rays and Earth's atmosphere. They come from exploding stars in the Milky Way and beyond. They pass through you - a trillion a day - and probably don't even know it. They're called neutrinos.

[The Ice Cube team celebrates the completion of the Ice Cube Neutrino Observatory.]

Neutrinos are tiny subatomic particles. They have almost no mass. They have a neutral electrical charge. They pass through matter undisturbed. Accordingly, they're all but undetectable.

Being able to detect neutrinos, however, could help us answer questions about our cosmos - questions about how stars die and about how our Universe was formed.

A week before Christmas, scientists who had been hard at work at the South Pole for the last six summers completed the installation of the world's largest neutrino observatory called 'Ice Cube.' (The scientists worked only during the warmer Antarctic summer months of November through February when there is nearly 24 hours of sunlight each day.)

The University of Wisconsin-Madison spearheaded the design and creation of the observatory that cost an estimated $270 million to build. Using a hot-water drill developed at the University, 86 holes were drilled in the ice, each over 2 km (1.25 mi.) deep.

Each hole houses a cable string of 60 soccer-ball sized optical sensors that was lowered to a depth of 1,450 to 2,450 meters (a mile to a mile and a half) below the surface. The holes will gradually fill in with ice until all 5,160 sensors are permanently embedded in the ice, forever on a neutrino hunt.

[One of the last strands of sensors is lowered into the ice at the Ice Cube Neutrino Observatory.]

Most of the trillions of neutrinos passing through the Earth on any given day go on their merry way without deviating from their course at all. Occasionally, however, a neutrino strikes an atom. The collision creates a burst of positively-charged particles called muons that race away from the neutrino. The burst is seen as a tiny flash of blue light called Cherenkov radiation.

The ice makes an ideal medium for observing neutrino-atom encounters. It's 100,000-year-old pure, compressed snow. It's clear and dark. When a neutrino collides with an atom in a water molecule somewhere in the one kilometer range of the Ice Cube observatory, the blue flash will be seen and recorded by one of the sensors.

By tracing the path of the particles in the blue flash, the sensor can find the origin of the neutrino. Since neutrinos have few interactions on their journeys through the cosmos, their paths lead directly back to their origins. Finding their origins will allow scientists to create a map of popular neutrino sources.

In fact, they've already started doing this, getting data from the partially-built observatory since 2005.

The observatory is expected to be fully operational by April once all of the instruments have been calibrated. Then, data that could give us a better picture of supernovae and black holes and tell us more about dark matter and dark energy should start arriving in earnest.

Update: To learn more about neutrinos and muons, listen to this Physics Buzz podcast:Exotic Particles

Monday, December 27, 2010

We know how airplanes glide in the air and how submarines move through water, but we don't know much about how creatures "swim" through sand. 'Til now...

How an object's shape affects its generation of lift and drag in both the air and in water is well understood. Otherwise, we'd be misplacing submarines all the time. But how objects - animals in particular - create lift and drag in granular materials like sand is less well understood.

A couple of Ph.D. students and their professor have been taking a closer look at what happens when sand-dwelling creatures - like lizards, crabs, snakes and worms - dive below the surface.

Goldman described the sandfish as a little lizard that lives in the desert in North Africa. When startled, it can burrow 10 cm beneath the surface in less than half a second. Its wedge-shaped head, which biologists believe gives the critter its lightning-quick burrowing ability, was the project's inspiration.

"We think the sandfish is the champion of rapid burial," Goldman said.

Another thing the trio noticed about the lizard, Ding said, is that its belly is really flat. "We thought that might have an effect," he said.

To test the theory on both the head shape and the belly, the team dragged three objects of different shapes through a container filled with tiny glass beads that acted as a sand analogue. They watched to see whether each object generated any lift - the force perpendicular to the direction of motion that "pushes" an object up.

The first was a cylinder. The team dragged it horizontally through the beads (if it were a Coke can, it would have been dragged from the dash in between the words "Coca" and "Cola") and measured the forces acting on it.

[Computer simulation of a cylinder being dragged through glass beadsshowing the beads' movement]

The cylinder experienced positive lift; it tended to rise within the beads, headed for the surface. A square rod was also dragged through the beads and it, too, rose towards the surface, but just barely. The third object was a half-cylinder. It experienced negative lift, sinking lower into the beads as it was dragged along.

[Computer simulation of a cylinder being dragged through glass beadsshowing the beads' speed: The brighter colored beads have a higher speed.The cylinder rises because it experiences lift.]

Of the three objects, the half-cylinder most approximates the shape of the sandfish lizard's head. Since the lizard also experiences negative lift when it enters the sand, the lab test showed that the half-cylinder was a good starting point for modeling the lizard's head.

[Video of a cylinder's trajectory over time when dragged back and forththrough plastic BBs. The cylinder is attached to a thin rod that slidesup and down freely. The rod has an LED at the top to show vertical movementover time. In this experiment, the LED shows that the cylinder experiences liftand rises over time.]

The researchers then dragged flat plates through the sand. The plates were given roughly the same angle of attack - or angle away from horizontal - as the leading edge of each of the objects. To mimic the cylinder, the first plate was at a very small angle almost perpendicular to the floor. Just as for the cylinder, the plate experienced positive lift.

The plate was then dragged forward at a 90 degree angle relative to the floor, and again, as with the cube-shaped rod, there was next to no lift. Then the plate was dragged at a wide angle, leaning back from the direction of motion like a lawn chair leans back from the surf at the beach. This time, as with the half-cylinder, there was negative lift.

These were exciting results for the researchers because they realized that they could break up the shape of any object into flat plates and sum them up in a computer model to see the forces acting on any object. In addition to showing lift, the models also helped them to understand how much drag, or force acting opposite the direction of motion, "tugging" on an object, was being produced.

"We found that we can basically understand the forces by decomposing them in flat plates," Gravish said. "You can build whatever object you want to see what forces it undergoes in granular materials."

A database of how objects respond when traveling through granular materials can be created simply by finding the sum of simple materials - the plates. Since there are no equations to describe locomotion in granular materials, the find was particularly exciting.

"What you really want to do in all this business is figure out the principles of what's going on," Goldman said. The results of this research have opened the door for the physicists to do just that.

On an earlier research project, Goldman's CRAB Lab used high-speed x-ray imaging to observe the lizard's movement when submerged. They found that it doesn't use its legs when swimming through sand, instead tucking them by its side and slithering like a snake.

[Earlier research showed that when "swimming" through sand, the sandfish lizard tucks its legs by its sides and slithers like a snake.]

Tuesday, December 21, 2010

Early this morning, something happened that hasn't happened in over 300 years - a total lunar eclipse occurred on the same day as the winter solstice, making Dec. 20-21 one of the longest and most unique nights of a lifetime.

Today, Dec. 21, is the winter solstice, the first day of winter in the Northern Hemisphere. The exact moment of the winter solstice - the annual moment when the North Pole is pointed furthest from the Sun - is at 6:38 EST.

Because the Earth's axis is titled, any given area on Earth's surface receives a different amount of sunlight each day. Looking at the diagram below of the Earth's yearlong orbit around the Sun, the Earth at the far right represents its position on the winter solstice.

Since the Northern Hemisphere is 'leaning' away from the Sun during the winter, it experiences shorter days and longer nights. Thanks to the axial tilt, northern points on the Earth spend more time in shadow during winter months. The winter solstice marks the day with the shortest amount of daylight and the longest night - the 24-hour period where the Northern Hemisphere spends the greatest amount of time in shadow.

In the same way that the Earth orbits the Sun, the Moon orbits the Earth. Sometimes, the three heavenly bodies align in such a way that the Earth is directly in between the Sun and the Moon. When that happens, there is a lunar eclipse: The Earth blocks the Sun from illuminating the Moon. What was a bright, silvery Moon can turn an ashy gray or a bright orange. It can even seem to disappear altogether.

It's rare for these two events - the winter solstice and a full lunar eclipse - to happen on the same day, but it does happen. It did this morning. The last time this occurred was in 1638. It won't happen again until 2094.

*Above is a timelapse video of this morning's lunar eclipse taken near the Washington D.C. area. The video spans a period of almost three hours, from just before 1:00 a.m. to around 3:30 a.m. It starts at the beginning of the visible lunar eclipse and goes through the first few moments after the total eclipse. It's my first foray into timelapse photography, so the results aren't perfect, but the video still got a 'wow' reaction once it was finished. (Though the moon's movement was predictable, controlling my tripod's movement wasn't nearly so.)

A few high clouds passed in front of the Moon several times which accounts for the sometimes hazy glow around the Moon. The images were taken every 20 seconds using a Canon 20D and a 300mm zoom lens. Variations in lunar surface brightness during the eclipse are mostly due to my manually throttling the ISO, f-stop and shutter speed settings.

On March 9, 2009, President Obama issued a memorandum asking his scientific adviser, John P. Holdren, the director of the office of science and technology policy, to develop the guidelines within 120 days. Despite that request, the guidelines are a full year and a half overdue. Ironically, the agencies targeted by the Dec. 17 memo are required to report back to Holdren on their progress in implementing the new policies within 120 days.

In his original memo, President Obama said that "Science and the scientific process must inform and guide decisions of my Administration," and that "The public must be able to trust the science and scientific process informing public policy decisions."

Though vague in terms of process, the Holdren memo calls for overall transparency among federal agencies. The memo is broken into four sections with a fifth section addressing implementation of the guidelines. The first two sections are the more relevant ones to the public.

The first section focuses on nurturing public trust in the government and its scientific research while also encouraging agencies to make their information available to the public. Section two expands on the policy of openness giving federal scientists the liberty to talk to the media about their research as long as it isn't classified material. The section further stipulates that public affairs officers cannot intervene to require a scientist to change his or her message.

The third and fourth sections talk about federal agencies' relationships with federal advisory committees and give government scientists more liberty to get involved within the private scientific community.

The request for the guidelines was one of the first executive orders of the Obama administration and it comes as a response to feelings by some that the Bush administration was too heavy handed towards science, in some cases controlling scientific information to better align with the administration's agenda.

The first two sections of the memo clearly address these sentiments, with the first bullet of the first section stipulating that "Political officials should not suppress or alter scientific or technological findings."

Though the guidelines are idyllic, they're ultimately a strategic move by the Obama administration. Though it is in itself an idyllic thought, the ideal would be for politics to be removed from science altogether. Whether or not this could really ever happen is another story.

Friday, December 17, 2010

Just in case you've been off the Grid (sorry, couldn't help myself), here's a reminder that "Tron: Legacy" opens today!

["Tron: Legacy" Trailer]

Confession: I'd never heard about "Tron" until about a week ago. (I know, I know.) I promise, however, that I really am a nerd. Just a young nerd. Luckily, another slightly older nerd friend a few cubicles over helped me get up to speed. (He told me about watching "Tron" on LaserDisc. What's that?)

The coolest thing about "Tron: Legacy", he said, was how the new movie comes full circle with the old. In the original movie, Kevin Flynn (Jeff Bridges) is turned into data and brought into the computer world by a teleportation laser.

The new film included Clu, Flynn's computer-based alter-ego who hasn't aged in the computer world. To re-create Clu for the sequel, a full-body laser scan of Bridges was taken and brought into a computer. Then, a digital mask of the actor's face was created and de-aged almost 30 years.

[Discovery News video about how actor Jeff Bridges was youthened for "Tron: Legacy"]

While playing the part of Clu during filming of the new movie, Bridges wore a helmet with four cameras mounted on it, each pointed at his face. The cameras recorded the movements of 52 dots drawn on the actor's face. Those movements were then fed to the computer mask where 52 corresponding points on the digital face moved in sync with the actor's real-life facial movements. (Click here for more on the making of "Tron: Legacy.")

The result is, well, pretty obviously CG. It's also really cool. And I, for one, can't wait to see it full feature. In the meantime, I hope the "Tron" following will still consider me a true nerd even though I was a little behind the curve.

[Original "Tron" Trailer]

Also, in case you need some help getting your nerd on, Wired Magazine (who went geekwild over Tron thismonth) blogged about the must-have "Tron" gear of the season. (There's more here.) Don't even think about trying to pick up a copy of the original 1982 movie, though, unless you're willing to shell out close to a hundred bucks. (I checked it out and it's true. Sorry. I'm bummed too.)

If you were hoping to see the original before going to see "Tron: Legacy" and you don't want to drop a Benjamin on it, there's a good video summary here. Fair warning: It contains spoilers.

The AGU Meeting in San Francisco this week was attended by an estimated 16,000 people. The crowds were massive and the lines for Starbucks were long. But perhaps nowhere was the excitement over all things geophysics-remotely-related more apparent during the evening business meetings focusing on each section of the Society.

After overdosing on posters for a few days, I sauntered over to the AGU business meetings and receptions on Tuesday evening, which are kind of like hospitality suites you find at many conferences, but with more hiking boots.

Each AGU section hosts a meeting/party, many with food and open bar. But even with inebriation, the climate still revolved around cutting edge science. In the meeting of the Cryosphere section, the discussion rang around Antarctica. In particular, the speaker, Helen Amanda Fricker, a glaciologist with Scripps Institution of Oceanography at the University of California, San Diego, who was accepting the 2010 Martha T. Muse Prize for Science and Policy in Antarctica, noted how complex it is to conduct scientific research on the Continent. It is inherently an interdisciplinary endeavor, she pointed out – you need oceanographers, geologists, meteorologists, seismologists, glaciologists, and although it was not specifically mentioned, you clearly need some physicists, if for anything, to lighten the mood on those long and dark nights.

But I didn’t think at that moment just how interdisciplinary the research can get. After the speeches, when the scientists swarmed the food line and I dove in, stole some eggplant sliders, and nearly lost my sense of humor (nothing gneiss about that! Sorry…), I had the good fortune of sitting next to Aqsa Patel from the University of Kansas, who clearly embodies this whole “everybody studies the cyrosphere” attitude. Turns out Patel is an electrical engineer, conducting research on new types of radar that is being used to analyze the ice sheets.

[Image courtesy of the University of Kansas: University of Kansas engineers with the Center for Remote Sensing of ice sheets prepare a radar system to look through several kilometers of ice to image the bedrock of Greenland]

The key is to use the radar, which is ground-based, airplane-based and even space-based (but somehow not affected by Earth’s mighty ring), to better understand how much ice is left, how fast it’s moving and how fast it’s melting. The goal, Patel said, is to validate the radar data with ice core and other data – essentially to double and triple check every sensor, and then use it to construct more accurate models of the cryosphere.

After that conversation, I somehow had a hankering for ice cream served on a mother board. But in the reception for the AGU Mineral and Rock Physics and Studies of Earth’s Deep Interior Section, all I found was Swiss cheese and artichoke dip. But fortunately, I bumped into another up-and-coming student in a different talk which filled my hankering for some great geophysics insights.

Kyle Warren, a grad student in geophysics at North Carolina State University, presented a paper this week on ocean acoustics. His poster, generated with colleagues and data from the Oregon State University and the Korea Polar Research Institute, was entitled “Underwater Acoustic Energy Generated by Drifting Ice in the Scotia Sea.” It delved into the contribution of natural noise to the undersea cacophony of man-made vessels, lost explorers and pirates, foreclosed mermaid colonies, and all those cute little worms at the bottom of the ocean. Apparently this was the first large-scale study into just how big the contribution of iceberg noise, in particular, makes to the overall noise level of the seas. And by the way, it’s pretty loud down there. The work will help scientists in many fronts, from marine science to glaciology to straight-up climate change. It could influence how marine animal scientists seek to develop techniques and protocols to better understand fauna behavior and how they are affected by the loud noise. And it will also undoubtedly even benefit the Bose Corporation, as they begin to develop noise-canceling headphones for dolphins, crabs and all the other fish in the sea.

Thursday, December 16, 2010

Strongest evidence for volcanoes spewing out ice from beneath the surface of Titan.

Astronomers have announced the discovery of a potential new ice volcano on Saturn's moon Titan.

Named Sotra, the volcano is more than 3,000 feet tall and has a one mile deep pit alongside it. Surrounded by giant sand dunes, it is thought to be the largest in a string of several volcanoes that once spewed molten ice from deep beneath the moon's surface.

“We think we have found the strongest case yet for an ice volcano on Titan,” said Randy Kirk, a geophysicist with the U.S. Geological Survey in Flagstaff, Ariz. “What we see is not just a flow like we see in other places, it's like a volcanic field would be on Earth.”

Titan is about the size of the planet Mercury but has an atmosphere thicker than Earth's. This makes it incredibly difficult for astronomers to know what's happening on the surface. Planetary scientists, including Kirk, are using NASA's Cassini spacecraft to map the moon, but so far only about half of Titan has been imaged.

Kirk and his team created a three dimensional mapping technique that patches together multiple images of the same area, so they were lucky that Sotra was in one of the rare places imaged twice.

“The classical volcano everybody thinks of when you say the word is a mountain with a crater on it and lava flows coming out of it,” said Kirk. “That's what we've found on Titan.”

The team can't be certain if the chain is active, but described the find as the best evidence found so far for a cryovolcano -- the scientific term for an ice volcano. Previously, bright spots seen in low-resolution satellite images have been interpreted as volcanic flows and craters. However, once those areas were mapped in 3-D, it became obvious they weren't volcanoes.

“We had noted Sotra Facula as a candidate cryovolcano before,” said Rosaly Lopes, a senior research scientist from NASA's Jet Propulsion Laboratory in Pasadena, Calif. “But it was only when Randy (Kirk) got the topography done that we realized, wow, this is it.”

Earth's interior is divided into distinct layers of rock and liquid magma. When this molten rock erupts through the planet's crust, it's known as volcanism. Titan's volcanism is more complicated because beneath the moon's surface lies a layer of ice. Even a small amount of internal heat could create molten ices. Because the liquid would be less dense, it would force its way to the surface. The result would be a massive eruption of slushy liquid and gases similar to what scientists have seen on other icy moons.

“Ice at outer solar system temperatures is very rigid,” Kirk said. “Ice at close to its melting point is soft. What would be a glacier on Earth would be a volcano on a body that's made of that same material. It's the difference between the cake and the frosting.”

Some have theorized that volcanoes on Titan are the best way to explain the strange abundance of methane gas in its atmosphere. This gas is constantly being stripped from Titan's upper atmosphere by the sun, shining a billion miles away. Without a source to replenish it, all of the methane would disappear in a few million years.

However, if an ice volcano like Sotra were to erupt, it would release volatiles like methane and ethane from inside Titan. Kirk's team calculates that it would take a Sotra-sized volcanic eruption every 1,000 years to maintain the current level of methane in Titan's atmosphere.

Others are skeptical about ice volcano claims and have proposed alternative theories to explain the methane abundance.

“There's been this whole list of volcanoes (on Titan) that have been published and then subsequently shot down,” said planetary scientist Jeffrey Moore, with the NASA Ames Research Center in Moffett Field, Calif. “This new feature doesn't make me change my tune that no one has unambiguously found a volcano on Titan.”

Moore believes that unlike Earth's well defined and separate layers, beneath Titan's surface is a huge layer of mixed rock and ice, or what's called a partially differentiated interior. If this is the case it would be much more difficult to heat ice enough to cause an eruption onto the surface.

Moore and others believe that Titan was once an enormous ice cube. According to their theory, as the sun aged and warmed, it heated Titan's surface. This process could have put methane into the atmosphere and subsequently fueled a rain-cycle that erased all impact craters. Moore said this would also have given Titan the young appearance that many have attributed to volcanism.

“If you press forward in time, all the methane will be erased and (Titan) will have a blue sky and a nitrogen atmosphere with sand dunes of hydrocarbons,” Moore said.

Wednesday, December 15, 2010

There may be a ring around the Earth, according to a consultant whose poster was presented at the American Geophysical Union (AGU) Annual Fall Meeting this week in San Francisco. And that ring might be affecting climate change.

But before you say “du’oh-f course!” to the idea that there’s a donut of particles circulating around the globe, know this: just as is the case with most controversial ideas in science, people are just about willing to come to blu’ows over it.

And so it was that while meandering through the poster fields of AGU I ran across the consultant’s poster and witnessed two scientists with elevated voices explaining to her that there was no way that there was a ring, akin to one of Saturn’s, ‘round the earth, with nobody knowin’ nothin’ ‘bout it before.

I asked one of the screaming nerds about the research before me and he suggested that she probably saw an anomaly in the climate data and was arguing a ring was the cause. But a ring that would be massive enough to contribute to climate change would have been observable, and yet, for some reason nobody seemed to notice it. Perhaps it was because we were so focused in on ET being found in a California lake that we missed all the crap floating mere miles into space.

No biggie. There was much more to see, do, and hear at AGU. Posters at the AGU Meeting play a big role, as big as talks, said one source. So I skipped over to another poster on the Planetary Sciences aisle and found that there is an elementary proposal in the works, as part of the Planetary Sciences Decadal Survey, to build and launch a Saturn Ring Observer.

As Matthew S. Tiscareno, a grad student at Cornell and one of the authors, explained it, the Observer would sit 3 km above Saturn’s rings and monitor how particles in the rings interact with each other. The particles, unbeknownst to the casual bystander, are constantly bumping into each other and clumping together. The rings move at a velocity of 10 km/sec, but the individual particles move at a relative velocity much slower – As Tiscareno, et al, notes in their poster, “Typical particle sizes in the rings of Saturn and Uranus are a few meters. Indirect evidence indicates that the vertical thickness of the rings is as little as 5 to 10 m which implies a velocity dispersion of only a few mm/sec.”

A Saturn Ring Observer would be the very first in situ spacecraft to directly study Saturn’s jewelry and help us better understand its microphysical reactions. Stay tuned…
Read the rest of the post . . .

Tuesday, December 14, 2010

Thirty-three years ago, on Sept. 5, 1977, Voyager 1 was launched for a journey to Jupiter, Saturn and beyond. Since then, we've seen the first space shuttle launch, the birth and death of compact discs, the introduction of the Chicken McNugget and both Bush presidencies. In those 33 years, Voyager 1 has seen quite a bit more and right now the probe is peering into the last reaches of our solar system.

After thirty-three years of zipping away from the Earth, Voyager 1 has reached the edge of our solar system, entering a realm where the Sun's plasma (hot ionized gas) no longer journeys.

Six years ago, the space probe left the "heliosphere," the bubble surrounding our solar system which is filled with charged particles (solar wind) emitted by the Sun, and entered the "helioshealth" - the last frontier before interstellar space.

Since June, scientists monitoring Voyager 1's Low-Energy Charged Particle instrument noticed that the solar wind speed was equal to the aircraft's speed, meaning the solar wind's speed was equal to zero. It's an indication that the probe is on the threshold of stepping beyond our solar system's edge.

"When I realized that we were getting solid zeroes, I was amazed," Rob Decker, a Voyager Low-Energy Charged Particle Instrument co-investigator and senior staff scientist at the Johns Hopkins University Applied Physics Laboratory in Laurel, Md., said in the NASA press release. "Here was Voyager, a spacecraft that has been a workhorse for 33 years, showing us something completely new again."

The scientists don't believe Voyager 1 has crossed over into interstellar space - the area between the stars - just yet, but they think it will sometime in the next few years. Right now, Voyager 1 is about 10.8 billion miles from the Sun, traveling at 38,000 mph.

Voyager 2, Voyager 1's sister probe which launched a few weeks before Voyager 1, is also headed for interstellar space. That probe is traveling more slowly, however, at 35,000 mph and, at a current range of 8.8 billion miles from the Sun, still has a ways to go before it encounters the edge of the solar system.

Both spacecraft were launched in 1977 to explore the outer planets - Jupiter, Saturn, Uranus and Neptune - a mission they completed in the late 1980s.

Monday, December 13, 2010

In the north of Ethiopia, about a hundred miles west of the southern end of the Red Sea, is a bubbling caldera known as "The Gateway to Hell." To get to it you must travel by camel train through some of the hottest, harshest terrain on Earth while keeping one eye open for the locals with a reputation for hostility.

This is Erta Ale, one of the Earth's oldest continuously active basaltic shield volcanoes so called for their shape resembling a warrior's shield. At the center of the volcano is a perpetually-bubbling lava lake every bit as menacing as it sounds.

Shield volcanoes form when rock deep in the Earth heats to its melting point and rises through conduits and fractures until it punches through the crust. Unlike explosive stratovolcanoes, like Mount St. Helens in Washington state, lava oozes out of shield volcanoes at a more lethargic pace.

Shield volcanoes are the biggest volcanoes on earth. They are short but wide with widths 20 times their heights. Their typical gradient is gentle at the bottom, near 2-3 degrees, with a steeper slope of 10 degrees near the top and they level out at the summit, producing the shield-like shape.

Erta Ale, which translates to "smoking mountain" in the local language, has been active since 1906. Its mile-wide elliptical summit resembles more a muddy quarry than a hazardous volcano, excepting, of course, the churning lava lake at one end. The lake is only one of five in the world, making the volcano quite a rarity.

With a viscosity a thousand times that of water, lava creeps along slowly enough to give humans enough time to get out of the way. Agriculture and infrastructure are common casualties of shield volcano lava, though, especially on the Hawaiian Islands - the most notable assembly of shield volcanoes.

Simmering at almost 2000 degrees Fahrenheit - 10 times hotter than boiling water - the molten rock at Erta Ale first fills up its circular chamber before spilling over, emptying out and receding back into the hole. The process repeats over and over like a giant piston in the Earth's crust.

In 2005, a major eruption at Erta Ale killed 250 heads of livestock and forced thousands of locals to evacuate but no humans were killed. Another eruption in 2008, however, resulted in two missing persons.

In 2009, a team of scientists led by Dougal Jerram from Durham University in the U.K. visited Erta Ale to map it. Using lasers, the team created a hi-res 3D photograph of the volcano's interior, obtaining the first laser scan of the inside of an active volcano.

The lava lake gateway to the underworld is just one of several exciting geophysical wonders in that part of Africa. In 2005, the nearby Dabbahu Fissure appeared overnight, spewing noxious volcanic gasses from the Earth's crust.

Both the volcano and the fissure lie along the Great Rift Valley, a geologically active area where the African plate is splitting apart, tearing the Horn of Africa away from the mainland. Though continental drift happens on a scale of eons, evidence of its violent nature can be seen in this extreme and ominous example in northern Africa. As long as you're willing to travel by camel train.

Friday, December 10, 2010

It's a typical December scenario: The family trip to the tree lot. The Fraser Fir tied to the roof of the car. Dad under the branches screwing the stand to the trunk. And the inevitable wobbling of the 7-foot holiday embellishment as it threatens to topple over and onto the floor, scattering needles everywhere. When it comes to holiday decorations, why do we work so hard to put out fragile items easily destroyed by Fifi and Fido? (Not to mention Frank and Francine...)

Holiday decorations are unstable. (We're talking about physics here. We'll leave their emotions aside.) To take a closer look at what we're dealing with, I've considered three of the most popular items from the array of December decor: The Christmas tree, the Hanukkah menorah and, of course, the Festivuspole.

Which of the three is the most likely to topple over when cousin Fred bumps into it after sampling too much egg nog?

Just as you would expect, the answer comes down to center of mass - that point in an object where its mass is concentrated. It's the same point an object rotates around when it spins - the same point an object wants to rotate around on its way to the floor.On a Christmas tree, the majority of the mass is concentrated near the floor. It has a low center of mass. The aluminum Festivus pole's mass is evenly distributed, putting its center of mass right near the center of the pole. For a menorah, with its branches at the top, it's center of mass is higher. That means the menorah would be the most likely to topple.

Just as we know it's hard to push a door open by pushing near the hinges versus near the handle, it's hard to topple an object whose center of mass is low to the ground. (For a longer discussion on this, check out this year's Thanksgiving post.)

Why, then, do those pesky trees make life so difficult for us? The reason Christmas trees topple so easily is because their base is so small. Anything making small contact with the ground relative to its size is going to be fairly unstable. It only has to be pushed past its edge of contact with the ground before it starts to tip over. (Trees have roots to prevent this problem in the wild.)

But what if I wanted to juggle them?

The menorah would be my best choice. "Why?" do you ask. When trying to balance something like a baseball bat or a broom in the palm of your hand, it's easier when the mass is concentrated at the top. Don't believe me? Try sticking a wad of Play-Doh at one end of a pencil. Now, try to balance the upright pencil on the tip of your finger. Is it easier when the Play-Doh is up in the air or when it's touching your finger? It's easier when it's up in the air.

Here's why: When the mass is concentrated further away from the pivot point - or point of rotation - it takes more force and more time for it to move. Think of an ice skater spinning. When her arms are stretched out, she spins more slowly than when they are tucked close to her chest.

Likewise, an object will tip over more slowly when it's center of mass is further away from the pivot point. If you're holding an object in your hand, a slower tipping time gives you more time to control the object and keep it from falling. That means the menorah, with the higher center of mass, will be easiest to control and easiest to juggle. Ta dum!

Thursday, December 09, 2010

They've got the flesh-gouging teeth and the powerful jaw muscles, but a new study suggests young great white sharks 8-10 feet long still have some growing to do before they're able to bite with the same legendary force of their larger elders.

New computer simulations show that the younger sharks just aren't able to handle such an intense bite. "[Their jaws] just couldn't handle the stress associated with big bites on big prey," said Stephen Wroe, a research biologist at the University of New South Wales near Sydney, Australia.

That stress can be substantial. A full grown great white shark can produce close to 4,000 pounds of force as it bites, which is about 20 times more powerful than what a human jaw can produce.

It's understandably difficult to take an in-depth look at a shark bite in the wild, so Wroe and his colleagues turned to a type of computer simulation often used by engineers that measures how much stress an object experiences as it works. Technicians use this "digital crash-testing" to test the performance of everything from car engines to space shuttle tiles.

The researchers discovered that a shark bite might be one of nature's most impressive crashes. For instance, the wider a shark opens its jaw, the more forceful its bite -- aided by the unique placement of muscles that powerfully slam shut the jaw at full gape.

That's a big difference from a mammal's jaw, in which the bite force weakens as the jaw opens wider, said Toni Ferrara, who was the lead author of a the Wroe study published Dec. 2 in the Journal of Biomechanics.

A great white shark who dines on larger prey like a seal lion needs a strong jaw when they open wide to take a bite. But the researchers found that this power only comes with age. The jaws of adult sharks are reinforced with a mosaic of calcium crystals that add stiffness and strength. Because younger sharks that are still developing this protective layer, said Wroe, the stresses on their jaws might not be ready to handle a full-force bite on when attacking prey.

The findings could also help to explain why great white sharks around 10 feet in length are not as consistent at successfully completing an attack on a seal or sea lion as their larger elders. But the younger sharks would actually like to eat these bigger animals if they could.

"They have a harder time chewing them," said biology professor Frank J. Schwartz, who studies shark behavior at the University of North Carolina's Institute of Marine Sciences in Morehead City, N.C. "They aren't as efficient as adults at tearing through the blubber."

This unexpected weakness of juvenile sharks is "likely to challenge public perceptions of these animals," said Ferrara. "They certainly aren't the omnipotent killing machines that some people see them as."

Wednesday, December 08, 2010

The center of a black hole is a mysterious place - a singularity where matter is concentrated into an infinitesimally small point and the laws of physics break down making anything possible. A year ago, a couple physicists said that we might be able to see into a black hole, to see a "naked singularity." Today, three physicists say that's not possible.

In October 2009, Ted Jacobson and Thomas Sotiriou published a paper theorizing that under the right circumstances it could be possible to see the center of a black hole. Now, in a new paper due to appear in Physical Review Letters, three physicists argue the Jacobson/Sotiriou theory, saying that no real-life circumstances would ever allow a singularity to be revealed.

To understand what we're talking about, we first have to understand a black hole's anatomy. A black hole's outer edge - called the event horizon - is defined as the "point of no return" where gravity is strong enough to trap objects traveling at the speed of light, not to mention any passersby going slower.

At the center of the black hole is a singularity, the area where matter is densely packed. We can't see beyond the event horizon, though, because everything inside is gravity-bound. No light can escape. That makes the singularity invisible to us.

But what if there was a way to destroy the event horizon, Jacobson and Sotiriou asked? Then we could see a naked singularity.

The duo said that if a spinning object collided with a black hole spinning in the same direction their combined momentum would allow the spinning force to counteract gravity enough to overcome the event horizon. No more trapping of light. We could see inside a black hole.

What would happen then is anybody's guess. It could mean the destruction of the universe. Because of that, scientists like Stephen Hawking believe in a cosmic censorship conjecture that requires singularities to be shielded by indestructible event horizons.

To come to their conclusion that an event horizon could be destroyed, Jacobson and Sotiriou used a mathematical simulation of a black hole. To do the difficult calculations, though, they had to discard some of the variables.

To understand what Jacobson and Sotiriou did, imagine that instead of simulating a black hole, they were simulating the Earth. To make the math easier, they effectively said the Earth was round, even though we know it is not. In reality, it is covered with small bumps like mountains and trees that, though small relative to the size of the Earth, do affect its gravity. Jacobson and Sotiriou ignored those bumps and their results told them that an object colliding with a black hole could disrupt the event horizon.

Enrico Barausse, Vitor Cardoso and Gaurav Khanna - the physicists with the latest paper - spent the last year adding some of those bumps back into the equation. Their results showed that as the object approached the black hole, the object's gravity would be enough to cause it to be deflected away from the black hole, keeping the event horizon intact.

Their research confirms the cosmic censorship conjecture, keeping any would-be naked singularities under wraps.

Tuesday, December 07, 2010

Inspired by the flexibility of an elephant's trunk, engineers in Germany have developed a "Bionic Handling Assistant" that is both light and flexible and could be used as a third arm in places ranging from industrial workshops to assisted living centers.

They were inspired by the flexibility of an elephant's trunk which has over 40,000 muscle fibers that allow it to move in any direction. Though it's not yet clear how the robotic arm could really be used, it is eerily similar to a real elephant trunk. That they were able to replicate the unique appendage with little more than plastic and air is pretty cool, too.

If you watch the video above, besides occasionally looking behind the trunk for the rest of the elephant's head, you'll probably have a strong reaction to the cool Festo inventions making cameos at the 2:15 minute mark. In case you wanted more, here they are in all their mesmerizing glory:

Now, if they would find a way to combine this elephant arm with the ingenious granular gripper, we'd be in business.

Monday, December 06, 2010

First, according to a doctor at the siesta competition, less than 30 percent of the contestants actually fell asleep. To make our lives easy, we'll say 100 people (roughly 28 percent) fell asleep.

Next, we'll assume that it took the average napper 10 minutes to fall asleep. Normally, people might average a longer drifting off time, but we're assuming these people are expert nappers capable of falling asleep quickly.

Multiplying those two numbers together, we can say that the total amount of napping done in the contest was 1,000 minutes.

Assuming each of the nappers works an office desk job, each would ordinarily burn 102 kilocalories (kcals) an hour at work. Over ten minutes, those 100 office workers would burn a combined 1699 kcals. Since a person burns about 61 kcals an hour while sleeping, we guess a collective 1016 kcals were burned by the nappers.

By subtracting the number of kcals burned while sleeping from working, we know that the net energy the nappers conserved was about 683 kcals, or 2.9 million Joules.

Friday, December 03, 2010

Newton's first law of motion says that at object at rest tends to stay at rest until acted upon by an outside force - like an alarm clock.

In case you missed it, a group of napping advocates, called the National Association of Friends of the Siesta, hosted a nine-day competition in Madrid, Spain, this October to see who could make the most of a 20-minute nap.

The contest was organized to revitalize the tradition of taking an afternoon siesta - a tradition that is dying out in Spain. Taking afternoon naps is not an uncommon practice around the world, but thanks to today's 24-hour-a-day, 7-day-a-week work lifestyle, fewer people are given the opportunity for a nap.

A 62-year old Ecuadoran man, named Pedro Soria Lopez, beat out 359 other contestants to take home the prize - $1400!!!

Lopez napped for 17 minutes. Though one of the runners-up napped for 18 minutes, Lopez scored extra points during his snooze for snoring at a peak of 70 decibels. (As loud as a vacuum cleaner!)

Contestants earned points for the amount of time they spent asleep - a maximum 20,000 points for a full 20 minutes - and also for flamboyant pajamas, unique sleeping positions (eh?) and, of course, snoring.

So, here's the Fermi problem:

Nearly 30 percent of the contestants actually fell asleep during the contest. Knowing that, how much energy did they conserve by sleeping and not working during the contest? (Math hint: Keep in mind that the Calories we see on our food labels are actually kilocalories.)

Thursday, December 02, 2010

The first nationwide count of parking spaces demonstrates their high environmental cost.

Next time you're searching for a parking space and someone grabs a spot from right in front of you, it might seem like the last space left on Earth, but ponder this: there are at least 500 million empty spaces in the United States at any given time.

The 250 million cars and trucks on America's roads get a bad rap for being environmentally unfriendly. Climate scientists say that automobiles add an array of greenhouse gases and harmful particulates into the Earth's atmosphere, yet little research has been done to estimate the impact parking spaces -- where those automobiles spend 95 percent of their time -- have on our planet."I think it's a surprisingly unknown quantity," said Donald Shoup, a UCLA urban planning professor and author of the book "The High Cost of Free Parking." "[Parking] is the single biggest land use in any city. It's kind of like dark matter in the universe, we know it's there, but we don't have any idea how much there is."

Civil engineers at the University of California, Berkeley recently published the first comprehensive estimate of parking spaces in America and found that the energy use and materials associated with creating hundreds of millions of parking spaces has a significant environmental impact.

The group had already published a study aimed at finding the environmental impact of America's total transportation infrastructure, but when they tried to estimate the impact of the nation's automobile infrastructure, they were forced to use the only existing national parking spaces study -- a count of just the 100 million metered parking spaces in the United States. A number of other environmental engineers were quick to call out the obvious limitations of using such a small number and convinced the team to attempt the first ever nation-wide count of parking spaces.

"We got some feedback from people saying 'We think you guys are drastically underestimating the amount of parking spaces in the United States,'" said researcher and lead author of the study Mikhail Chester.

Chester pointed out that if there are 250 million cars in the country, obviously there must be at least that many spaces for people to park at home -- add in spaces for work and shopping and it becomes apparent that there must be many times more than 100 million parking spaces. The researchers' estimates included things like street side parking, building code requirements, parking garages, lots in megastores like Walmart and Target and then parking spots at work and home.

Even defining a parking space is a difficult task, so the group focused on several primary groups of paved spaces; free and metered on-street spaces; surface parking, or ground spaces like those found in front of big box stores and in people's driveways; and multi-story parking structures.

Because of all the uncertainties, they decided to examine the environmental impact of five different scenarios for parking. The first scenario was limited to only the 100 million metered parking spaces in the previous study. The next three scenarios examine what the group considers to be the most likely situation -- that there are somewhere around 800 million parking spaces in the United States, or nearly three official parking spaces for every car on the road.

The final case was the most extreme of the scenarios. The researchers extrapolated on a rule of thumb used by urban planners that claims eight parking spaces exist for every one car. The group says that there is little science to support this scenario, but the result would be a whopping 2 billion parking spaces. If all of those spots were consolidated into a single location they would cover an area the size of Massachusetts. The most likely scenario calls for about half that area in parking spaces.

“The environmental effects of parking are not just from encouraging the use of the automobile over public transit or walking and biking,” the group stated in their paper, “but also from ... activities related to building and maintaining the infrastructure.”

"There's actually a larger infrastructure for parking than for roadways," said Chester. "This speaks to the sort of hidden infrastructure components that are there to store our vehicles when they're not moving."

Once the parking estimates were completed, the researchers calculated the energy requirements as well as the emissions from creating asphalt and other things associated with constructing and maintaining those parking spaces. They then added their estimates to the emissions caused by an average vehicle.

Their results are considerable, even when compared to the environmental effects of driving a car. The group found that parking contributes to greenhouse gases like carbon dioxide, methane and nitrous oxide. In fact, the environmental cost of so many parking spaces can also raise the amount of carbon dioxide emitted per mile by as much as 10 percent for an average car. And, when calculated over the lifetime of a vehicle, the amount of other gases like sulfur dioxide can rise by as much as 25 percent and the amount of soot as much as 90 percent.

Sulfur dioxide and soot are both harmful to humans and are associated with things like acid rain and respiratory illnesses.

"We've traditionally thought about the environmental impact of parking as being limited to the heat island effect," said Chester, referring to the process by which large areas of asphalt are thought to heat cities to higher temperatures than surrounding rural areas. "The amount of parking has a rather drastic impact on the energy and emission contributions from vehicles."

Shoup said that the informal calculations he's done produced parking space estimates similar to the Berkeley teams, but adds that he thinks the impact of driving cars still dwarfs the environmental cost of parking.

"Only in the last 5-10 years have we been giving some thought to whether there should be an abundance of free parking," said Chester. "Ninety-nine percent of automobile trips end in free parking and this has a major effect on people's choice of what means of transportation to take."

Wednesday, December 01, 2010

Talking about their values could help women do better in physics courses according to a joint study by the University of Colorado and Stanford University.

I remember my first day of Physics II in college. I sat near the back of the room, one of two or three girls in a classroom full of men led by the stereotypical beard-adorned professor. To call that atmosphere intimidating would be an understatement.

Recent research conducted at the University of Colorado (C.U.) worked to tackle that very anxiety felt by women studying male-dominated subjects, like science, technology, engineering and math, where there's a stereotype that men outperform women.

"Women are affected by the stereotype threat because of the idea that men generally do better than women in physics," Akira Miyake, professor of psychology at C.U. and co-author of the research paper, said.

Six C.U. researchers, half physicists and half psychologists, incorporated writing exercises into an entry-level physics course required for students working on science degrees (as opposed to liberal arts majors, for example).

Three-hundred ninety nine students were given writing assignments twice in the semester, once during the first week of class and again during the fourth week of class, right before their first mid-term exams.

One group of students was asked to choose from a list of 12 or so values, like relationships with family and friends or learning and gaining knowledge, and spend 15 minutes writing about why those values are important to them. Another control group was given the same list of values and asked to choose two or three that were not important to them and explain why others might see them as important.

For women in the values affirmation group - the group that explained why several values were important to them - there was a discernible improvement in grades both on in-class exams and on an end-of-term national standardized test. In that group, 41 percent of the women earned C's while 37 percent earned B's. Compared to the control group, where 56 percent of the women earned C's and 23 percent got B's, the improvement was obvious. (There was no improvement shown among women scoring A's.)

The researchers believe that having women take time to affirm their abilities and self-worth in a classroom environment that is known for breeding anxiety helped them to feel more reassured at the start of the course, an attitude that likely snowballed for the remainder of the semester. The students repeated the exercise as a homework assignment before their first exam. It might have helped them do better on the exam, resulting in good grades early in the semester and better overall grades by the end of the term.

The women were also given a survey that asked them whether they believed in the stereotype that men do better in physics than women. For women who didn't believe in the stereotype, there was no real difference. Women who did believe in the stereotype, however, showed the greatest improvement. Additionally, there was no difference in the men's grades as a result of the exercise, leading the researchers to believe that it's all about the stereotype.

Miyake said the group intends to do more research to see whether women studying in other male-dominated fields would respond similarly.

"The natural question," he said, is "whether this works in other teaching situations." Since the writing exercise was unrelated to physics, the team believes the effects could be repeated in other areas where women might feel intimidated. Miyake also said he believes that if the exercise proves effective enough to be implemented, it should be done even earlier, perhaps in high school or middle school when women are first introduced to physics.

Though the researchers have yet to replicate their study and fully digest how these exercises affected students' grades, one thing that is immediately apparent is instructors must consider psychological factors, including a student's beliefs and academic history, in addition to material when engaging students.

"It's important that we as a community of physicists, teachers and instructors pay attention to things that are broader than just content," Noah Finkelstein, associate professor of physics at C.U. and another co-author of the paper, said.